[PATCH 1/3] ARM: debug: use kconfig choice for selecting DEBUG_LL UART

Nicolas Pitre nico at fluxnic.net
Sun Aug 21 17:00:46 EDT 2011


On Sun, 21 Aug 2011, Russell King - ARM Linux wrote:

> On Sun, Aug 21, 2011 at 04:07:37PM -0400, Nicolas Pitre wrote:
> > On Sun, 21 Aug 2011, Russell King - ARM Linux wrote:
> > 
> > > And further to this, I'll point out that the debugging functions are
> > > *explicitly* designed to avoid corrupting any more than just r0-r3
> > > and lr.  That's not just the IO functions but also the hex and string
> > > printing functions.
> > > 
> > > And the head*.S code is explicitly written to expect r0-r3 to be
> > > corrupted - which basically means that no long-term values are held in
> > > those registers.
> > 
> > Well, not exactly.  I actually have a patch to that effect I made a 
> > while ago so all the early code could be unaffected by inserted function 
> > call, but held on to it because nothing yet justified its need.  Here it 
> > is for reference:
> 
> And so this buggers up the ability to insert calls to the debugging code
> by placing values into r0-r3.  So that patch will get a nak too.

What?  Please look again at the patch and tell me what is wrong with it.
Because I can't make sense of your last sentence.


Nicolas



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